The purpose of this study is to determine the impact of HIV infection on hepatitis C virus (HCV) liver disease outcome, and the prevalence, risk factors, and viral and immunologic characteristics of liver disease in HCV-infected hemophiliacs, both HIV(+) and HIV(-). Approximately 826 HCV-infected hemophiliacs from 10 U.S. hemophilia treatment centers will be available for study. This group is unique in that patients are well characterized, closely followed, the time of HCV infection is known, HCV infection duration is greater than 20 years, and the incidence of liver disease progression is increasing. The specific objectives of this study include: (1) a cross-sectional cohort study in which hemophiliacs with HCV infection, both HIV(+) and HIV(-), are enrolled and undergo transjugular liver biopsy to determine the prevalence of cirrhosis and fibrosis progression rate. (2) a cross-sectional study comparing HCV-infected patients, both HIV- and HIV+, to determine clinical, life-style, and laboratory, e.g. biochemical, serologic, molecular biologic, and immunologic characteristics associated with development of cirrhosis and stage of fibrosis progression. (3) a cytokine study, comparing cytokine mRNA levels, interleukin-6 (IL-6), interleukin-10 (IL-10), and transforming growth factor-beta (TGF-beta 1 and TGF-beta 2) in liver tissue, cytokine immunoassay levels in plasma, and cytokine expression genotypes with liver histopathologic score and with fibrosis progression rate in prospectively-biopsied hemophiliacs.